1. Field of the Invention
The present invention relates to a safety device for data storage devices such as the registration section of an electric desk-top calculator with a built-in memory function or the data setting section of a light measuring meter or any other measuring instrument which includes a plurality of push-button switches, key switches, sensor switches or the like in such a section.
2. Description of the Prior Art
Recent measuring, calculating or controlling instruments such as electronic desk-top calculators and various measuring instruments, are often provided with push-button switches, key switches, sensor switches or the like for data inputs. With such switches, any desired data input and setting can be attained merely by pushing or touching them, resulting in facility of operation. Contrary to this advantage, they are also disadvantageous in that they are liable to be inadvertently operated, resulting in an inadvertent change of set or input data that must be maintained for a desired time period, thereby preventing a correct resultant value. This causes inconvenience and loss of productive time to the user of the device or instrument.
Japanese patent application Laid Open No. 55-87139 is of general interest in disclosing an underwater camera with a plurality of switches for data input and a water pressure responsive switch that is capable of disabling the data switches by grounding their terminals.
The prior art is accordingly seeking a relatively inexpensive approach to protecting data from inadvertent erroneous data input.